1. Field of the Invention
The present invention concerns a method of sweetening an aqueous sugar-containing juice containing sugar and calcium ions and is more particularly concerned with a method of regenerating ion exchange resins in the process of decalcification of sugar factory juices.
2. Description of the Prior Art
During the processes employed in the manufacture of sugar, the juice obtained by diffusion from sugar beet converted into cossettes is treated with lime. The spent cossettes are pressed to produce pulp. The lime introduced into the juice is converted into calcium carbonate by introducing carbon dioxide. The calcium carbonate is eliminated by filtration. However, this elimination is only partial and a certain quantity of calcium compound remains dissolved in the juice in the form of soluble calcium salts. These calcium salts have a certain degree of solubility which decreases if the concentration of dry materials increases, which occurs during the evaporation and crystallization steps. On precipitating, these calcium salts deposit tartar on the equipment and reduce the coefficient of thermal transfer, which causes partial disruption to the equilibrium of the economics of sugar factory. Furthermore, they cause turbidity in the crystallized sugar obtained during the process.
Decalcification is therefore needed to keep the equipment clean and to obtain sugars of quality, that is to say without turbidity. The calcium ions are exchanged by means of ion exchange resins for sodium and/or potassium ions and the resin is then regenerated. Regeneration was initially effected with brine, NaCl, but this method of regeneration has now been abandoned in most countries since it produces waste water charged with chlorides.
Two types of regeneration are currently used, the Akzo or NRS process and the Gryllus process.
The Akzo process, consisting in regeneration using soda, involves a considerable expenditure of soda and an increase in the coloration of the clarified juices.
In the Gryllus process, regeneration is effected using Green Syrup II. The drawbacks of the Gryllus process are third strike precipitation of calcium salts, Standard Liquor 1 (LS1) recycling and turbidity in the first strike sugar.
The present invention overcomes the problems of prior art regeneration techniques.
In the method of the present invention molasses is used to regenerate ion exchange resins of the sugar factory juice decalcification process.